Bell, being thus convinced, maintains that many of our facial muscles are "purely instrumental in expression;" or are "a special provision" for this sole object. But the simple fact that the anthropoid apes possess the same facial muscles as we do, renders it very improbable that these muscles in our case serve exclusively for expression; for no one, I presume, would be inclined to admit that monkeys have been endowed with special muscles solely for exhibiting their hideous grimaces. Distinct uses, independently of expression, can indeed be assigned with much probability for almost all the facial muscles.
Sir C. Bell evidently wished to draw as broad a distinction as possible between man and the lower animals; and he consequently asserts that with "the lower creatures there is no expression but what may be referred, more or less plainly, to their acts of volition or necessary instincts." He further maintains that their faces "seem chiefly capable of expressing rage and fear." But man himself cannot express love and humility by external signs, so plainly as does a dog, when with drooping ears, hanging lips, flexuous body, and wagging tail, he meets his beloved master. Nor can these movements in the dog be explained by acts of volition or necessary instincts, any more than the beaming eyes and smiling cheeks of a man when he meets an old friend. If Sir C. Bell had been questioned about the expression of affection in the dog, he would no doubt have answered that this animal had been created with special instincts, adapting him for association with man, and that all further enquiry on the subject was superfluous.
 `Anatomy of Expression,' 3rd edit. pp. 98, 121, 131.
 Professor Owen expressly states (Proc. Zoolog. Soc. 1830, p. 28) that this is the case with respect to the Orang, and specifies all the more important muscles which are well known to serve with man for the expression of his feelings. See, also, a description of several of the facial muscles in the Chimpanzee, by Prof. Macalister, in `Annals and Magazine of Natural History,' vol. vii. May, 1871, p. 342.
 `Anatomy of Expression,' pp. 121, 138.
Although Gratiolet emphatically denies that any muscle has been developed solely for the sake of expression, he seems never to have reflected on the principle of evolution. He apparently looks at each species as a separate creation. So it is with the other writers on Expression. For instance, Dr. Duchenne, after speaking of the movements of the limbs, refers to those which give expression to the face, and remarks: "Le createur n'a donc pas eu a se preoccuper ici des besoins de la mecanique; il a pu, selon sa sagesse, ou--que l'on me pardonne cette maniere de parler--par une divine fantaisie, mettre en action tel ou tel muscle, un seul ou plusieurs muscles a la fois, lorsqu'il a voulu que les signes caracteristiques des passions, meme les plus fugaces, lussent ecrits passagerement sur la face de l'homme. Ce langage de la physionomie une fois cree, il lui a suffi, pour le rendre universel et immuable, de donner a tout etre humain la faculte instinctive d'exprimer toujours ses sendments par la contraction des memes muscles."
Many writers consider the whole subject of Expression as inexplicable. Thus the illustrious physiologist Muller, says, "The completely different expression of the features in different passions shows that, according to the kind of feeling excited, entirely different groups of the fibres of the facial nerve are acted on. Of the cause of this we are quite ignorant."
 `De la Physionomie,' pp. 12, 73.
 `Mecanisme de la Physionomie Humaine,' 8vo edit. p. 31.
 `Elements of Physiology,' English translation, vol. ii. p. 934.
No doubt as long as man and all other animals are viewed as independent creations, an effectual stop is put to our natural desire to investigate as far as possible the causes of Expression. By this doctrine, anything and everything can be equally well explained; and it has proved as pernicious with respect to Expression as to every other branch of natural history. With mankind some expressions, such as the bristling of the hair under the influence of extreme terror, or the uncovering of the teeth under that of furious rage, can hardly be understood, except on the belief that man once existed in a much lower and animal-like condition. The community of certain expressions in distinct though allied species, as in the movements of the same facial muscles during laughter by man and by various monkeys, is rendered somewhat more intelligible, if we believe in their descent from a common progenitor. He who admits on general grounds that the structure and habits of all animals have been gradually evolved, will look at the whole subject of Expression in a new and interesting light.